1. Field of the Invention
The present invention relates to an optical component used for recording and reproducing signals to and from an optical disc, an optical pick-up device using the optical component, and an optical disc apparatus using the optical pick-up device.
2. Description of Related Art
As to conventionally used optical pick-up devices, there has been used several kinds of beam splitters in order to contrive the isolation between a light emitting source and an optical detecting system. By the way, since demands for miniaturizing optical pick devices has been increased, there are such a trend that optical units in which a light source and an optical detecting system are packed in one and the same package have been produced.
In order to materialize the above-mentioned optical unit, an optical component formed thereon with diffraction gratings have been used. Japanese Laid-Open Patent No. H10-154344 discloses in detail the technical configuration of the optical component as an example. Thus, since such an optical component has been materialized, the optical pick-up device has become small-sized, and accordingly, small-sized optical disc apparatus each incorporating a small-sized optical pick-up device have been commercially available.
By the way, the miniaturization and widespread of optical disc apparatus have caused new problems. For example, the miniaturization inevitably causes a light emitting source, a detecting element and an optical component are arranged in close proximity with one another. Further, the long time use thereof and enlargement of utilization thereof for recording causes the optical output power of the light emitting source to be increased, and as well the working temperature thereof is also raised. Further, similar to note-book type personnel computers which have been widespreadly used, the use of the optical component in a small-sized housing causes the environmental temperature to rise up further.
As the working temperature range in which optical units should be used is enlarged, affection by thermal expansion coefficients of components constituting the optical unit comes into force. For example, should the dimensions and positions of the optical components which are formed thereon diffraction gratings be affected, the provability of such a fact that servo control causes errors or offsets would become higher.
The present invention is devised in order to solve the above-mentioned problems, and accordingly, an object of the present invention is to provide an integrated optical component with which variation in working temperature does not affect an optical detecting system which can realize detection of signals which can hardly be affected by cross-talk, and also provide an optical pick-up device using the integrated optical component, and an optical disc apparatus using the optical pick-up device.
To the end, according to the present invention, there is provided an integrated optical component for guiding an optical emitting beam from an optical emitting element to an optical disc, and for picking up required beams from reflection light from the optical disc, incorporating therein a plurality of optical surfaces any one of which is formed thereon with a diffracting grating for extracting optical beams required for tracking control and focusing control, from the reflection light.
Further, there are provided an optical pick-up device using the above-mentioned integrated optical component, and an optical disc apparatus using the optical pick-up device.